The bank then shared indicators of compromise with other institutions and a number of those other organisations confirmed that they too had been compromised.

These ‘watering hole’ attacks attempted to infect more than 100 organisations in 31 different countries.

Symantec has blocked attempts to infect customers in Poland, Mexico and Uruguay by the same exploit kit that infected the Polish banks. Since October, 14 attacks against computers in Mexico have been blocked, 11 against computers in Uruguay and two against computers in Poland.

Preliminary investigations suggested that the starting point for the Polish infection could have been located on the web server of Poland’s financial sector regulatory body, namely the Polish Financial Supervision Authority (www.knf.gov.pl).

Commenting on this news, Ilia Kolochenko (CEO of High-Tech Bridge) said: “We should expect that cyber criminals will find more creative and reliable ways to compromise their victims. Trustworthy websites, such as governmental ones, represent great value for cyber criminals, even if they don’t host any sensitive or confidential data.”

Kolochenko continued: “In the past, hackers used one-off or garbage websites to host malware, but as corporate users become more educated and vigilant, attackers need to find more reliable avenues to deliver malware and enter corporate networks. That’s why Gartner, as well as other independent research companies, continuously say that the risk posed to corporate web applications is very high and seriously underestimated. Spear phishing and watering hole attacks against high-profile websites will grow significantly in the near future.”